


Worth It, It's Worth It

by Mistress_of_Undertail



Category: Undertale (Video Game)
Genre: Ecto Genitals, Ecto-Tongue, Fanwork of Fanwork, Forced Orgasm, Keep that in mind ;), M/M, Rape, Sans is roughly 14, Short, Soul Rape, Soul Sex, Underage Rape, dubcon, for the second half, non-con
Language: English
Status: Completed
Published: 2016-05-31
Updated: 2016-05-31
Packaged: 2018-07-11 08:27:09
Rating: Explicit
Warnings: Rape/Non-Con, Underage
Chapters: 1
Words: 3,480
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7040800
Author URL: https://archiveofourown.org/users/Mistress_of_Undertail/pseuds/Mistress_of_Undertail
Summary: <blockquote class="userstuff">
              <p>Based on the fic, To Love Yourself by undertailsoulsex...</p><p>An explicit account of Sans' bad time with Doctor W. D. Gaster during his later childhood.</p>
            </blockquote>





	Worth It, It's Worth It

**Author's Note:**

  * For [undertailsoulsex](https://archiveofourown.org/users/undertailsoulsex/gifts).
  * Inspired by [To Love Yourself](https://archiveofourown.org/works/6424108) by [undertailsoulsex](https://archiveofourown.org/users/undertailsoulsex/pseuds/undertailsoulsex). 



> This is an in depth, explicit and raw look into Sans' past that was revealed in Chapter 23 of undertailsoulsex's fic, To Love Yourself. I highly recommend reading up to that chapter or at LEAST that chapter before continuing with this one.
> 
> This was 100% author approved (she gave me all the inside details) and even wrote the small piece between the skeleton brothers in the middle. Everything else was done by me. 
> 
> Thank you for reading. And again, please be mindful of the tags. Read with caution.

* * *

 

 

Sans rubbed his eyes as he was led by the hand down the corridor, still sleepy. He didn't know what the doctor wanted him for, especially in the middle of the night, but Dr. Gaster wouldn't explain and had told him to be quiet. Sans was too tired to complain. He just hoped whatever it was, it would be quick and he could go back to sleep. Papyrus was still deep asleep in their room and he wanted to join him.

The doctor led him to the same room they always used for Gaster's "tests." It was a cold room with a gurney set in the middle and a metal cabinet with wheels standing beside it. Sans didn't think anything about it, sitting on the sterile paper draped over the bed like he'd done a dozen times before.

"is this going to take long?" Sans finally asked, looking up at the doctor. It was the first time the doctor wanted to do this at night and so he was curious. "...is there anything wrong?" he asked when he didn't get an answer.

"...LIE DOWN. IT'LL BE OVER SOON, I PROMISE."

Sans let out a frustrated sigh, but obediently did as told, laying down on the gurney. He shifted a bit on the paper, getting comfortable. He wondered if maybe he could just fall asleep here. Sure the experiments wouldn’t be exactly pleasant, but they weren't anything new.

Then Gaster secured the straps on his wrists. Okay, that was new.

Still, Sans didn't think too much of it.

"IS THIS COMFORTABLE?" the doctor asked as he tightened them.

"um...sure. they're fine." Sans watched him more carefully, trying to read his expression. "is...is this going to hurt..."

The doctor smiled and Sans felt a shiver run up his spine.

"WELL...THAT DEPENDS ON YOU..."

Sans eyes widened as he felt the doctor's hand on his naked thigh bone. It slowly slid up, moving under his medical gown.  "d-doctor...?"

"SHH...TRY TO BE STILL, SANS. BE GOOD FOR ME..."

Sans pulled on his restraints as the hand crept higher, brushing against his naked pelvis. "what are you... no! s-stop!"

"SHHH. IT'LL BE OVER SOON. THAT'S IT...YOU HAVE SUCH LOVELY BONES, SANS..."

God, the way he said it. Sans tried to escape his touch, squirming away from his hand. Gaster grabbed his ankle and firmly pulled him back down on the bed. Sans gasped sharply. The doctor continued to fondle him, his fingers rough and invasive. Sans shuddered, shutting his eyes as he felt his entire face burn with humiliation and panic. Gaster's touch ran across the front of his pelvis, then the back, stroking his tail bone.

It sent shivers of revulsion up his spine...as well as the hint of something else.

"no...s-stop! why are you...stop it!"

He had to make him STOP! Sans' eye burned as it flashed and bones appeared above the gurney, shooting towards the doctor. But Gaster just had to raise a hand and they froze mid-air and simply vanished.

"I'M DISAPPOINTED, SANS." His other hand never stopped, groping him roughly and Sans gasped and grunted under the treatment. "I THOUGHT YOU WERE MUCH SMARTER THAN THIS."

Gaster finally let him go, but it was obvious he was just starting. The doctor leaned against the edge of the table and used both hands to slide Sans' gown up to his collarbones, exposing his quivering naked body.

Sans brought his knees to his chest, twisting away from Gaster, pulling on the restraints. Tears were beginning to gather in the corners of his eye sockets. God, why...why was the doctor doing this to him? Had he done something wrong? Was this a punishment for something? His soul throbbed.

"stop! let me go!"

The doctor ignored him, pushing down his knees so his legs lay flat on the table. He pinned both his thin ankles with one hand, gripping them painfully tightly. Sans trembled, looking away as Gaster's eyes roamed his body, an awful hungry look on his face. He regretted looking away immediately when he felt something slide under his rib cage, cold, bony fingers wrapping around his soul. An icy chill shot straight through him.

Sans gasped sharply, tears running down his face as he struggled harder. "NO! STOP! WHAT ARE YOU-DON'T PLEASE!"

More bones appeared, his magic appearing on its own now, fueled by his panic and horror. But the doctor waved them away easily again. Gaster pressed the sharp tip of his thumb into the center of Sans’ soul. Hard.

"NGH!" Sans body jerked on its own, his eye lights turning to pinpricks. It felt like he had been stabbed. It hurt. God, it hurt.

"DON'T FIGHT, SANS. YOU CANNOT WIN." The doctor's voice was tinged with laughter. "AND BELIEVE ME, I WON'T HESITATE. I'LL KILL YOU IN AN INSTANT IF THAT'S HOW YOU WANT TO PLAY."

Sans' vision swam in front of him as Gaster leaned close, his hot breath spilling onto his neck. "AND I'M SURE PAPYRUS WON'T FIGHT. HE MAY EVEN ENJOY IT. WHAT DO YOU THINK? SHOULD I GO AND FIND OUT?"

Sans trembled violently and the tears fell in earnest now. He couldn't stop them, couldn't stop _him_. Powerlessness choked him, suffocated him. "...d-don't....o...okay...i...i...i won't...i won't fight...please...leave my brother alone..."

He turned his head away from Gaster, but could practically feel his wide grin. The doctor still had his soul in his grasp and his twisted emotions flowed through him, his rush of satisfaction, his pleasure at the submission, his lust...

Sans cringed as he felt the doctor's tongue run along the side of his face.

"GOOD. I KNEW YOU WOULDN'T DISAPPOINT ME, SANS."

The doctor climbed onto the table and Sans shuddered. The walls, the ceiling, looking anywhere else was better than the monster in front of him. He stopped pulling on the restraints, relaxing his body as best he could, but his bones continued to rattle on their own. He had no control over his own body. Over what was happening. Over anything. God, please...make it stop.

Gaster leaned over him, pressing his teeth against Sans' sternum, before sliding his slippery, purple tongue along the bone. A loud moan escaped Sans' mouth against his will as his soul was stroked, the broad side of the doctor's thumb rolling gently over the sensitive organ.

"YOU'RE SO BEAUTIFUL, SANS. I WANTED YOU...FOR SO LONG NOW."

Sans chanced a glance. His soul was throbbing in Gaster's hand, the organ slick now from the caresses, its blue juices coating the doctor's fingers.

"VERY BEAUTIFUL..."

Sans cried out, throwing his head back as the doctor brought his hand back to his pelvis, stroking his pubis at the same pace he squeezed his soul. It was...too much.

An entrance materialized on its own and Sans' face burned hot with shame. How dare his body betray him. He felt so disgusting, even as undeniable pleasure surged through his bones via his soul, or because of it.

"LOOK AT YOU. OH SANS...SO YOUNG AND..."

Sans’ eyes widened and he gasped sharply, his spine arching off the table as the doctor slipped two long, soul-slicked fingers inside him. His legs trembled, his mind going blank. This...this couldn't be happening...

"...STILL SO TIGHT. GOOD. BETTER NOW THAN WHEN YOU'RE OLDER...YES. MMMM."

Sans could feel him stroking his insides, rubbing against the walls. It felt so pervasive, so wrong. He trembled, sobbing. "please...s-stop...no..."

Gaster ignored him, his fingers moving harshly, eliciting both moans and sobs out of him. He trembled and panted, the pleasure and revulsion mixing so it never felt truly good, nor truly horrible. Just stuck in between ecstasy and horror.

"SANS. BE A GOOD BOY NOW. MY BOY."

Sans gasped softly as Gaster removed his fingers. He sniffed, muffling his sobs against his teeth. He didn't want to look. God, he didn't want to. But the pause was unbearable. He finally turned his head.

It was as if Gaster had waited for him to look. The doctor had unzipped his pants and pulled out something Sans hadn't seen before. Oh, he had seen his own short, thick blue member a few times in the past. But this...

He almost didn't recognize what he was seeing. It was large and very thick, glowing a dark shade of purple. Its tip was glistening with a drop of purple liquid that grew until it ran down its length. Gaster stroked it with a soft groan.

"SANS..."

The doctor took hold of Sans’ thigh bones, spreading them apart so they lay on either side of Gaster's mostly-clothed waist. Sans looked away as Gaster leaned over him on the table, his mouth pressed against his neck, his breath hot and thick. "REMEMBER. DON'T FIGHT."

Sans whimpered and sobbed, Gaster's previous threat ringing loudly against his skull. Then there was a blinding pain as Gaster pushed inside and the warning evaporated along with every other thought in his mind as he screamed.

It was too much. Too much!

"NO NO NO! STOP STOP! PLEASE!! PLEASE! ST-AH! NGH!!!"

Sans' screams broke apart as Gaster began to move, grunting against his skull. Sans was stretched open and penetrated to his very limit, over and over again. It felt like he was being ripped apart from the inside. To make it worse, Gaster still had his soul in his hand, now squeezing in an iron grip. Both pain and pleasure seared his mind, like an actual brand. Hot and painful.

It was too much.

He choked on his cries, drool sliding down his chin, tears running freely down his face. He couldn't even form words of protest anymore, couldn't fight even if he wanted to. Gaster violated him utterly and all he could do was take it.

"YES...OH YES SANS...SO GOOD."

The thrusting came harder, faster. Sans grunted, his entire body tensing up against the violent invasion. He was only aware of a single thought...

_god...let it end...just kill me...please..._

Faster and faster, the sound of their bodies colliding, the doctor's moans and his grunts of pain filled the silence of the room. Darkness edged around Sans’ vision and he faintly wondered if he was blacking out. But that would have been a mercy.

"SANS!"

He felt Gaster's teeth sink deep into his neck and suddenly everything came alive, bright and blinding. He could feel every inch of his body, as if an electric current had ripped through every limb. His bones tightened around his restraints, his magic tightening around Gaster inside him. Sans screamed.

The doctor thrust deeply one last time, his entire body shuddering, and growled against Sans' shoulder. Sans felt something hot and alive spill inside him, felt it invade every inch of him, mixing with his own magic. It felt dirty. Slimy. Disgusting. And now it was part of him. Forever.

There was a moment of respite, Gaster panting against his neck as he caught his breath. Finally, the doctor pushed himself off Sans' trembling body. Sitting up, he looked down at him, the edges of his grin pulling into a smirk.

"HOW NICE OF YOU...TIGHTENING UP LIKE THAT AT THE END. I KNEW YOU'D LIKE IT."

Sans shuddered, but said nothing. The tiny pinpricks of his eye-lights went to his soul that was still clutched in Gaster's hand. The doctor followed his gaze and turned to the small heart-shaped thing. It was utterly drenched, coating his entire palm. It throbbed and pulsed slowly, as if drained and limping. Gaster ran his long tongue along it and Sans shuddered, letting out a hoarse groan.

"DELICIOUS."

The doctor chuckled darkly, a bit breathlessly after the act they just shared. Carefully, he placed the soul back under Sans' ribcage and unstrapped his restraints. Sans just lay there, breathing as if every breath took effort.

Gaster jumped off the table and fixed his gown. Sans didn't even flinch as the doctor stroked his face, his eyes trained to the ceiling, unseeing.

"LET'S GET YOU TO BED, SHALL WE? ...COME."

There was a subtle edge to his voice at the last word and Sans flinched, becoming more alert. Moving as if his entire body would shatter to dust at any moment, he sat up and slid off the table. Gaster took his hand and pulled him out of the room, as if nothing they had done had happened.

As if they had simply finished conducting another experiment. Gaster strolled casually, almost uplifted. He could have whistled and Sans wouldn't have thought it out of place.  
It was in that moment Sans realized. This was going to happen again. He was sure of it.

And there was nothing he could do to stop him.

Nothing.

Sans didn’t know how long it took to get to his room. It felt like no time at all. He blinked and was roughly pushed inside. Gaster slammed the door behind him, casting the room into absolute darkness. His bones wouldn’t stop rattling. The noise filled the room, filled his head. It just wouldn’t stop.

“Sans?” came his brother’s sleepy voice from the far side of the room. “Are you okay?”

He couldn’t reply. Not because he didn’t want to. He wanted to reassure his brother that everything was fine and to tell him to go back to sleep. But his voice wouldn’t work. He opened his mouth over and over, trying to find the words, but nothing would come out.

There was a shuffling of blankets and he could hear Papyrus’ tiny pitter-pattering footsteps as he crossed the room.

“Did you have a nightmare?” His brother’s voice was ever so gentle.

Sans nodded, praying that Papyrus could see the movement in the dark. He must have, since his brother wrapped his thin arms around him, pressing his head into Sans’ ribcage.

“Brother, you can wake me up if you have a bad dream. I’m always here for you!”

Sans choked out a sob and crushed his brother tighter against him.

Finally finding his voice, he sobbed out, “i know.”

Papyrus’ kind eyes met his and in that moment Sans knew he had made the right decision. It was worth it. All of it was worth it if it meant he had protected his brother from that… creature.

But he had to make sure that the doctor never went near Papyrus. At all costs.

 

 

*******

 

 

It became routine. Not every night, but it was a near thing.

For months, Gaster took out his stress, his frustrations, his lust out on Sans and he...took it.

Oh, did he take it. He even took it with a forced grin if it meant his brother was safe from the hell he endured. True, it wasn't all pain, but he didn't even come close to anything Gaster must had felt during their moments together. Sans lost count of how many fake orgasms he pulled in order to satisfy that monster.

So, this time shouldn't be any different.

Gaster groaned deeply where he sat behind his desk. Sans was on his knees, his mouth wrapped around the doctor's cock. He worked diligently as he put his mind as far away from what he was doing as possible. He liked to think up and solve math equations for this sort of thing. Still, he kept some attention to what he was doing. He still needed to satisfy him after all.

Sans ran his tongue along the underside, swirling against the frenulum before taking it back down his throat, using his magic to suck and swallow. He glanced up. The way the doctor was moaning, he was hoping maybe it would be a short session this time. Despite how much the aftermath made him sick, it was better than the alternative.

"GOD SANS...YOU'RE DOING SO WELL."

Sans had long since learned to drown out his words, even if they still haunted his nightmares. Though perhaps he ignored him too well. Gaster suddenly stood, knocking him back a bit. Sans looked up, eyes wide. _..shit.._

He flinched as the doctor lifted him up and pushed him against his desk. Sans turned away as Gaster kissed his neck, his fingers trailing up his hospital gown — even in his office, the doctor never gave either him or his brother proper clothing — stroking his ribs. Sans inhaled. God, he hated when the doctor did this. He hated when it felt good.

It was just a precursor for the pain.

"YOU'VE BEEN SO GOOD LATELY. LET ME RETURN THE FAVOR...."

Sans blinked then suddenly gasped sharply, arching his back. This...this was...

Gaster had leaned down and under his gown. Sans trembled and shivered as he felt the monster's tongue slide against his naked pelvis where usually he used his fingers. It wrapped around his pubic bone, rubbing harshly, before the slippery appendage slid inside the hole above the ischium.

"...f..fuck...ga...gaster..."

Oh it felt good. Oh it felt, really, really good. Oh no...

His arms, holding him up against the desk, began to tremble and it wasn't long before his magic swirled and formed around that invasive tongue, embarrassingly fast.

"THERE YOU GO." Gaster raised his head and forced Sans to look at him, pressing their mouths together.

Sans had long since stopped fighting this, opening his mouth and letting the doctor inside, greeting it with his own. He shivered, tasting himself. It was new and distracted him for a moment. Only a moment.

He cried out loudly against Gaster's mouth as the doctor roughly brought him down fully onto his cock. He winced, pain shooting up his spine. Gaster didn't bother waiting, never did, moving harsh and fast, pounding against him. Sans grit his teeth and bore it. But...but something was different. He had been so wet that Gaster's cock slid inside easily and hit against his walls in such a way that...

Sans moaned, arching his neck, cursing softly. What was this? _What was this?_

"ENJOYING YOURSELF?" the doctor chuckled against his neck, making him tremble.  
Sans ignored him as best he could, but suddenly cried out again as Gaster pressed a thumb right against the sensitive nub right above where they were joined.

"...f-fuck...g..g-gaster...i...ah! p-please..."

Gaster licked his neck and Sans knew what was next, what always came next. But god, it was...it was different. Heat and pleasure mixed with the pain, overwhelmed it at times, his bones shuddering from the sensation. That damn hand kept pressing, rubbing against his clit as he was pounded into, the entire desk shaking from the force of it.

Gaster panted against his shoulder, his hot breath making him shudder.

"COME FOR ME," he breathed before sinking his teeth into his neck.

And he did.

Sans’ eyes snapped wide open at the pain and he cried out, arching his spine. Gaster slammed hard into him and Sans tightened around that hot, throbbing cock. Suddenly everything went white and a rush of pleasure ripped through him, gushing out from where they were joined, every limb going rigid. It was both incredible and overwhelming...but it lasted only a minute.

Sans collapsed back against the table, panting in a daze. He felt the doctor's cum run down his legs and the feeling made him tremble with another surge of pleasure, too lost to be disgusted. He moaned.

Gaster pulled out of him, eliciting another gasp, and fixed his pants, watching him with utter satisfaction.

"GOOD TO KNOW WHAT THE REAL THING LOOKS LIKE."

Sans cursed. So he did know. He tried to get up, his arms and legs wobbly. Gaster simply watched him for a moment, eye sockets narrowed. Sans was too much in a daze to see it coming. The doctor grabbed his wrist and yanked him forward.

Sans lost his balance and came tumbling off the desk, his chin smashing against the hard floor. He saw stars.

"NEVER LIE TO ME AGAIN. THIS IS YOUR ONLY WARNING."

"...f..fuck."

Gaster straightened his coat and walked away, closing the door with a soft click.

Sans curled into a ball on the floor under the desk, the pleasure he felt now a distant memory. He knew eventually he'd have to get up, clean up the mess, and somehow return to his room, where Papyrus would be waiting for him, safe and protected. But not right now. Right now he...he needed a moment.

He hugged himself tightly. It was worth it, he told himself. What he always told himself, even as his body ached, even as his mind reeled from the memory of what must have been his first real orgasm of his life, even as he shuddered as he realized Gaster could still violate him in new and surprising ways.

Even as the tears fell.

It was worth it.


End file.
